Photoluminescent floor tile

ABSTRACT

A photoluminescent tile composition made of a tile base and a matrix of photoluminescent material disbursed throughout the tile base. The tile base includes a non-transparent mineral filler. The photoluminescent material located on exposed surfaces absorb and release light. The same manufacturing methods and equipment used to manufacture conventional floor tile can be used to manufacture floor tiles from the tile composition.

This is a continuation-in-part of my co-pending U.S. application Ser.No. 10/147,740 filed May 16, 2002.

FIELD OF THE INVENTION

The invention relates to flooring, particularly flooring made from anontransparent filler such as limestone or clay.

BACKGROUND OF THE INVENTION

Buildings are provided with emergency signs marking exits and fireescape routes. The signs direct persons out of the building in the eventof fire, natural disaster or other emergency. Often, however, electricservice is lost during the emergency and the building interior goesblack. Persons are unable to find the escape routes or follow them, andremain in the building.

Backup lighting is often relied upon to provide illumination whenelectric service is lost. Backup lighting systems include batteries oremergency generators that power emergency lights. The lights are locatedat exits and along escape routes throughout the building.

Although valuable, backup lighting has disadvantages. The backuplighting system must provide coverage of all escape routes. Extensivecoverage can be expensive to install. Preventative maintenance iscritical, because the system's mechanical and electrical systemcomponents must operate reliably during the emergency. Furthermore, thesystem must be capable of providing sufficient illumination forsufficient time to enable escape from the building.

Because of these disadvantages, non-powered lighting systems have beendeveloped to supplement backup lighting. These systems usephotoluminescent materials to provide light. A photoluminescent materialabsorbs light energy and then releases the light energy when in thedark. The material absorbs light from normal ambient light and releasesit during a blackout. The material “glows in the dark” independently ofthe backup lighting system to mark emergency exits or escape routes. Thematerial can release light for hours, and provides failsafe lightingthat complements backup lighting systems.

A conventional photoluminescent system employs laminated sheets ortiles, each tile having a light-emitting layer above a non-luminescentbottom layer. The light-emitting layer is formed from plastic or epoxyresin that incorporates a matrix of photoluminescent material. Thebottom layer may be made of vinyl or epoxy and attaches the tile to afloor or wall. The light-emitting layer provides illumination.

Although photoluminescent systems are useful, there is room forimprovement. Photoluminescent systems require additional labor toinstall them. The tiles have a relatively small surface area and can beused only in limited areas. Often the photoluminescent tiles do notprovide a pleasing appearance under normal light.

Thus, there is a need for an improved photoluminescent system. Theimproved system should be easy to install and be labor-efficient. Thephotoluminescent areas should have relatively large surface area andhave a pleasing appearance under normal light.

SUMMARY OF THE INVENTION

The invention is an improved photoluminescent floor tile that glows inthe dark during a blackout. The improved floor tile can replaceconventional floor tile and has the appearance of conventional floortile under normal lighting. During a blackout, the entire floor glows toprovide an extensive, failsafe supplemental photoluminescent lightingsystem.

A photoluminescent floor tile in accordance with the present inventionis formed from a tile composition made from a tile base and a matrix ofphotoluminescent material disbursed throughout the base. The baseincludes a nontransparent filler, preferably a limestone or clay fillerfor long wear. The same manufacturing methods and equipment used tomanufacture conventional floor tile can be used to manufacture the floortiles of the present invention.

Some of the disbursed photoluminescent material is located on the topsurface of the tile. This material absorbs and discharges light to andfrom the tile. Photoluminescent material preferably makes up betweenabout 2 percent to about 20 percent by weight of the combined weight ofthe base and photoluminescent material. This provides effective particledensity on the top surface of the tile. Wear of the tile exposes freshphotoluminescent material so that the tile retains its ability to glowin the dark despite heavy use.

Floors formed from the tiles of the present invention are installed inthe same manner as conventional floor tiles. Installing a floorautomatically installs a photoluminescent backup system at no additionallabor cost.

The tiles of the present invention are not limited to just backuplighting systems. The tiles can also be combined with conventional tileto generate interesting visual displays that appear when the lights areturned off. This enables businesses to offer customers a unique andappealing light display in addition to conventional decoration schemes.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawings illustrating photoluminescent floor tiles of thepresent invention, of which there are four sheets of five embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a first embodiment floor tile in accordance withthe present invention;

FIG. 2 is a sectional view of the floor tile shown in FIG. 1, the viewtaken along line 2—2 of FIG. 1;

FIG. 3 is a closer view of the tile shown in FIG. 2;

FIG. 4 is a top view of a first tile arrangement made of tiles as shownin FIG. 1 and conventional tiles;

FIG. 5 is similar to FIG. 4 but illustrates a second tile arrangement;

FIG. 6 is a top view of a second embodiment floor tile in accordancewith the present invention;

FIG. 7 is a top view of a third embodiment floor tile in accordance withthe present invention;

FIG. 8 is a view similar to FIG. 2 of a fourth embodiment floor tile inaccordance with the present invention; and

FIG. 9 is a view similar to FIG. 2 of a fifth embodiment floor tile inaccordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-3 illustrate a first embodiment floor tile 10 in accordance withthe present invention. The tile has a top surface 12 and a bottomsurface 14. The illustrated tile is 12 inches by 12 inches square andapproximately one-tenth of an inch thick. Other embodiments of floortile can have different shapes or dimensions.

The tile 10 is formed from a tile composition that has photoluminescentparticles 16 uniformly disbursed throughout a tile base 18 (theparticles 16 are representated as black dots in FIGS. 1 and 2 andrepresented by circles in FIG. 3). The particles 16 are firmly embeddedin the base 18 and together form a rigid floor tile.

The photoluminescent particles 16 preferably consist of anon-radioactive photoluminescent pigment. A suitable pigment is formedfrom rare earth materials. These photoluminescent pigments are eachcharacterized by low toxicity, short excitation time, high brightnessand long glow life. One such pigment is formed from strontium aluminatehaving a europium activator, and may be the Series G-200, Y-200, B-200or V-200 photoluminescent pigments available from Way2glo, Inc.,Thousand Oaks, Calif. (or functional equivalents).

The photoluminescent particles form a matrix of particles 16 embedded inthe base 18. The particles are disbursed throughout the thickness of thetile 10 between the top and bottom surfaces of the tile. A number of thephotoluminescent particles 16, however, are located on the top surfaceof the tile. These particles can absorb and emit light from and to theambient environment.

The tile base 18 is conventional and formed from resin, plasticizer andfiller used in the production of conventional floor tiles. The resin andplasticizer form a thermoplastic binder system. The filler is preferablyground limestone and ground ceramic. The filler is not required to betransparent. Other colorant or ornamental particles can be added.

In general, the photoluminescent material constitutes between about 2percent to about 20 percent by weight of the tile 10. This providessufficient particle density on the top surface of the tile 10 to achievesatisfactory illumination levels. The proportion of photoluminescentmaterial can be increased or decreased to modify illumination levels orto compensate for luminescence variations or particle size amongdifferent types of photoluminescent materials.

A representative tile formulation composition is:

Material Amount (pounds) Ground limestone (60 mesh) 112 Ground limestone(80 mesh) 144 Acetate vinyl resin 17 Stabilizer 1 Vinyl Resin 23 Lineremix 65 Line Dust 37 Plasticizer 16 Photoluminescent material 106

The same ingredient (except for the photoluminescent material) can beused to manufacture conventional, non-self-luminescent floor tiles.Preferably the photoluminescent material is provided as a fine,free-flowing powder to facilitate mixing with the other ingredients.

The ingredients are placed in a shearing mixer and are thoroughly mixed.This ensures that the photoluminescent particles 16 are distributedevenly throughout the mixture. The mixer heats the ingredients to about280 degrees F. The heated mixture is discharged from the mixer andpasses through a roll mill to form a blanket. The blanket is about 80mils (0.080 inch) thick. The blanket is heated and rolled several timesin a conventional manner to partially cross-link the polymericingredients and form a finished gauge blanket. If desired, a waxovercoating can be applied in a conventional manner. The sized andfinished blanket is transferred to a press that punches individual tiles10 from the blanket.

The tiles 10 are installed in the same manner as conventional floortile. This enables a photoluminescent backup system to be installedsimultaneously with floor installation—without additional labor orinstallation time.

Each floor tile 10 appears to be a conventional floor tile under normalambient lighting. The photoluminescent particles 16 on the top surfaceof the tile 10 absorb light from the ambient lighting. Ambient lightingcan include sunlight, fluorescent lighting or incandescent lighting.Less than one hour of light exposure is typically required to charge thephotoluminescent particles 16.

The particles 16 release light and supplement backup lighting during ablackout. The tile top surface 12 glows in the dark and illuminates thefloor. If an entire floor were formed from tiles 10, the entire floorwould be illuminated. Buildings having floors or hallways formedentirely from the tiles 10 would have the full length of escape routesilluminated. Known photoluminescent pigments can illuminate the escaperoutes for ten hours or more.

Photoluminescent tiles 10 can also be combined with conventionalnon-luminescent floor tiles. FIG. 4 illustrates a floor forming aportion of an escape route. The floor includes a number of like floortiles 10 (each shown with an “X”) and non-luminescent tiles 20. Thetiles 10 and 20 are otherwise identical in composition except that thetiles 10 contain the particles 16. The tiles 10 and 20 appear identicalunder normal light, and so the floor normally appears to be madeentirely from the conventional tiles 20.

In a blackout the tiles 10 glow and illuminate an area surrounded by thedark conventional tiles. In addition to illuminating the escape route,the tiles 10 are arranged to provide useful indicia. In FIG. 4 the tiles10 are arranged to define an arrow indicating direction along the escaperoute. Other indicia could be designed as desired. Tiles made of thesame composition as the tile 10 but formed in other shapes could be usedto form parts of the indicia.

Photoluminescent tiles 10 and non-luminescent tiles 20 can also becombined to provide special lighting effects or displays. FIG. 5illustrates a floor in which the tiles 10 and tiles 20 are arranged inan interlocked herringbone pattern. Under normal lights the tiles 10 and20 appear identical. The floor appears uniform with no herringbonepattern visible. Turning off the lights displays an illuminated,glow-in-the-dark herringbone pattern extending along the floor.

The tiles 10 can create floors with visually appealing light patternsthat appear in the dark. In other embodiments the tiles 10 and the tiles12 can be made from tile bases of different color and forming a firstpattern when lighted and a second, entirely different, pattern when thelights are off. The number of glow-in-the-dark patterns is limited onlyby the imagination, and can include other bond patterns, checkerboardpatterns, geometric shapes, words, or borders. Dance floors, skatingrinks, outdoor sidewalks and convention centers are some of the venuesthat could provide entertaining floor displays for customers.

The tile 10 has photoluminescent particles distributed throughout theentire top surface of the tile to present a uniformly illuminated tilein the dark. FIG. 6 illustrates a second embodiment floor tile 110 inaccordance with the present invention. The tile 110 is similar to thetile 10 but photoluminescent particles are found only in spaced-apartregions of the tile surface.

The tile 110 includes a first base 112 formed conventionally fromlimestone filler. The base 112 does not contain photoluminescentparticles. Disbursed throughout the base 112 are a number of veins orseams 114. The veins 114 are distributed throughout the thickness of thetile 110 and are formed from a second base 116. The second base 116 islike the base 18 and includes a matrix of photoluminescent particles.

The bases 112 and 116 preferably include contrasting coloring agents togive a mottled appearance to the tile 110. The coloring agents can bethe same as used in conventional mottled tile. The base 112 is usually alighter color than the base 116.

The photoluminescent particles in the surface veins 114 located on thesurface of the tile 110 absorb and emit light as previously describedfor the tile 10. Under normal lighting the tile 114 appears identical toa conventional mottled tile. In the dark, the veins 114 on the surfaceof the tile emit light and glow in the dark. The surface area of theveins 114 is sufficient to provide adequate illumination.

The base 112 can be made from the same ingredients listed above for thebase 18 but without the photoluminescent material. The base 116 can bemade from the same ingredients as the base 18.

The same manufacturing methods and equipment used to manufactureconventional mottled floor tile can be used to manufacture the floortiles 110. The base 116 is heated, mixed and rolled into a blanket aspreviously described for the base 18. The blanket is sent to a crusherthat breaks the blanket into pieces. The broken pieces are stored forlater processing.

The ingredients for the base 112 are placed into the shearing mixer andare heated and mixed. Broken pieces of the base 116 are then added tothe mixer. Typically the broken pieces make up about one-third of theentire mixture by weight. The entire mixture is then mixed for about anadditional 40 seconds. This ensures the broken pieces are disbursedthroughout the mixture.

The mixture is discharged and processed into tiles as previouslydescribed. The pieces of the base 116 form the elongate veins 114disbursed throughout the base 112. These veins 114 are represented asellipses in FIG. 6 and form a jaspe or striated tile appearance.

FIG. 7 illustrates a third embodiment floor tile 210 in accordance withthe present invention. The tile 210 includes a base 212 like the base112 and veins 214 similar to the veins 114. The tile 210 has the samecomposition as the tile 110 and is made the same way except that thecrushed pieces forming the veins 114 are mixed in the mixer for only 40seconds. The resulting tile 210 has a marbled appearance, as representedby the rectangles representing the veins 214.

In other embodiments of mottled tile each of the bases may include amatrix of photoluminescent particles. Under normal lighting the tilewould have a mottled appearance. In darkness the entire top surface ofthe tile would glow.

FIG. 8 illustrates a fourth embodiment floor tile 310 in accordance withthe present invention. The floor tile 310 is similar to the floor tile10 but includes a substrate or carrier 312. The lower surface of a wearlayer 314, having the same composition as the floor tile 10, is bondedto the carrier 312. A tile overcoating 316 covers the upper surface ofthe wear layer 314. The overcoating 316 is preferably a clear, thin filmof urethane or wax. For clarity the relative thicknesses of thesubstrate, wear layer and overcoating are not drawn to scale.

The substrate 312 and the overcoating 316 are the same as that used inthe manufacture of conventional non-luminescent vinyl tile flooring andso will not be described further. The wear layer 314 includesphotoluminescent particles 318 (like the particles 16) disbursedthroughout a tile base 320 (like the tile base 18). The areal density ofphotoluminescent particles 318 on the top surface of the wear layer ispreferably the same as that on the top surface of the tile 10.

The tile 310 is manufactured in a manner similar to that of the tile 10.The tile base and the photoluminescent particles are mixed together andheated to cross-link the polymeric ingredients as previously described.The blanket formed from the tile base and photoluminescent particlesmixture is applied to the substrate 312. The blanket and substrate arebonded or fused together in the same manner as used in manufacturingconventional tile (typically by calendaring or heating or both), and theovercoating is applied.

The tile 310 may also be manufactured by mixing the tile base and thephotoluminescent particles together and applying the mixture withoutheating to the substrate. The mixture and substrate are then bondedtogether by calendaring or heating (or both) and the overcoating isapplied.

In yet other embodiments similar to the floor tile 310, a blanket ortile base and photoluminescent particle mixtures used to form mottledfloor tiles can be bonded to the substrate.

FIG. 9 illustrates a fifth embodiment floor tile 410 in accordance withthe present invention. The floor tile 410 is similar to the floor tile310 and differs only in its wear layer 412. The wear layer 412 includesa nonluminescent tile base 414 (like the tile base 18) withphotoluminescent particles 416 (like the particles 16) disbursed throughthe tile base.

Unlike the previous embodiments, the photoluminescent particles 416 arenot disbursed throughout the entire thickness of the tile base 414.Instead, the particles 416 are limited to an upper portion of the tilebase adjacent the upper surface of the tile as shown in the figure. Theareal density of photoluminescent particles 416 on the top surface ofthe wear layer is preferably the same as that of the wear layer 314.

To form the tile 410, the tile base 414 ingredients are mixed and formedinto a blanket as in making a conventional tile. The photoluminescentparticles 416 are “dusted” or distributed over the top surface of theblanket. The dusted blanket is rolled to embed and disburse theparticles into the upper portion of the blanket. Other materials todecorate or color the upper surface of the blanket can also be dustedonto the blanket. The finished gauge blanket is then overcoated and thetiles are punched from the blanket as previously described.

A mottled photoluminescent tile can be achieved by dusting only spacedapart areas of the blanket with the photoluminescent material.

In an alternative method of manufacture of the tile 410, a blanketformed from a mixture of tile base ingredients and photoluminescentparticles, like the mixture forming the tile 10, is placed on top of ablanket formed from a mixture of tile base ingredients withoutphotoluminescent particles. The two blankets are heated and rolledseveral times in a conventional manner to partially cross-link thepolymeric ingredients and form a single finished gauge blanket.

The upper blanket can be similar to those used to form mottled floortiles to provide a mottled photoluminescent tile.

In yet other embodiments of the present invention the tile base may besuitable for manufacturing ceramic tile. A ceramic tile base is formedfrom a clay filler mixed with other ingredients, including quartz,kaolin, talc and the like. The mixture is molded into tiles and thetiles are glazed and fired in an oven or kiln. A ceramic tilecomposition in accordance with the present invention includesphotoluminescent material mixed or dusted with the ceramic tile base.The photoluminescent material illuminates the exposed surfaces of thetiles as described for the tile embodiments described above.Photoluminescent ceramic tile of the present invention is otherwisemanufactured using the same equipment and methods as nonluminescentceramic tile, and can be installed like conventional ceramic tile.

The photoluminescent material must be capable of withstanding firingtemperatures. Strontium aluminate pigments, for example, are suitablefor ceramic tiles because such pigments typically do not dissociate attemperatures less than 1200 degrees Centigrade.

The photoluminescent material can make up by weight more than 20 percentof the ceramic tile composition. Generally, ceramic tile compositionsare not as dense as limestone tile compositions. The same volume ratioof photoluminescent material to the entire tile composition mixtureresults in a greater percentage by weight of photoluminescent materialin the ceramic tile composition than in the limestone tile composition.

While I have illustrated and described preferred embodiments of myinvention, it is understood that these are capable of modification, andI therefore do not wish to be limited to the precise details set forth,but desire to avail myself of such changes and alterations as fallwithin the purview of the following claims.

1. A rigid tile comprising: a non-photoluminescent substrate; a wearlayer having a top surface, and a bottom surface, said bottom surfacebeing bonded to said substrate; a non-transparent inorganic materialwithin said wear layer and forming a substantial portion of said wearlayer; a thermoplastic resinous binder within said wear layer, theweight of said inorganic material being substantially greater than theweight of said resinous binder, the ratio of said inorganic material andsaid resinous binder being about 4.5; and a photoluminescent materialwithin at least an upper portion of said wear layer, adjacent to the topsurface such that said wear layer illuminates after ambient light hasbeen removed.
 2. The tile according to claim 1 wherein said inorganicmaterial is approximately 65% of the total weight of said wear layer. 3.The tile according to claim 1 wherein said resinous binder isapproximately 15% of the total weight of said wear layer.
 4. The tileaccording to claim 1 wherein said photoluminescent material isapproximately 20% of the total weight of said wear layer.
 5. The tileaccording to claim 1 wherein said inorganic material within the wearlayer is limestone.
 6. The tile according to claim 1 wherein saidresinous binder is one or more vinyl resins.
 7. The tile according toclaim 1 wherein the photoluminescent material is dispersed within saidwear layer as fine particles.
 8. The tile according to claim 7 whereinthe photoluminescent material is dispersed through out the entirethickness of the wear layer.
 9. The tile according to claim 8 whereinthe wear layer further comprising an upper portion adjacent to the topsurface and a lower portion adjacent to the bottom surface and whereinthe photoluminescent material is dispersed only in the upper portion ofsaid wear layer.
 10. The tile according to claim 1 wherein the substrateis a vinyl tile flooring material.
 11. The tile according to claim 1further including an overcoating layer positioned over said wear layer.12. The tile according to claim 11 wherein said overcoating layer istransparent.